Chusetts



April 30, 1929'.

R. H. MAURER PILOT CUT-OFF FOR GAS BURNERS Filed Sept. 16 1927 Patented Apr. 30, 1929.

UUNITE'I'.) STATES PATENT OFFICE.

Burns 11. MAURER, or ianooxnmn, MASSACHUSETTS, 'nssrenon T srruvcnn THER- mosrn'r comm, or CAMBRIDGE, MAssAcHUsE'rrs, A CORPORATION or mnssm cnusnrms.

rIto'r our-Orr r03. eAs BURNERS.

Application fi led September 16, 1927. Serial No. 219,940.

r This invention relates to gas burners and more particularly to heating gas burners, which in some cases are-provided withpilots for relighting them when necessary, and having automatic means for cutting off the flow of gas in the event that the pilot and the main burner are extinguished.

Heating by gas is now very common for water heaters, stoves and certain types of automatic refrigerators and it is. customary to vary and in some cases to cut off the heat applied'by automatic or manually controlled devices, the burners being often relatively inaccessible. For the purpose of insuring the continuous automatic action of burners of this character, it is customary to provide a pilot to relight the main burner when necessary, although the pilot need not be used if the controlling means is adapted merely to regulate the height of the flame of the main burner. lit sometimes happens in this latter case that the flame in the main burner is accidentally extinguished, or in the case where a pilot is usedand the main burner is intentionally extinguished, the ilot also goes out; so that when the flow 0 gas to the main burner is reestablished, it is not ignited, but escapes to the surrounding parts of the-building in which the burner is located with the attendant risks to the occupants both from fire and asphyxiation.

Among the objects of the invention, therefore, are to provide an automatic shut-off responsive to the burner and to the pilot if one is used, which will'function quickly and in a certain manner to cut off the flow of gas to the main burner in the event that the flame in both the main-burner and pilot, if one is used, is extinguished; to provide in a device 4 of this character a cut-off valve so located as tobe out of the heat range of the burner and consequently more, durable and less likely to get out of order; to provide means associated with the pilot or the burner for insuring a generally to improve devices of this character. l.

v Other objects and advantages of the invention will be apparent from the following specification and appended claims when taken in conjunction with the accompanying drawings, in which:

Fig. 1 is an elevation of a burner and thermostat associated therewith; and

positive action of the cut-01f means; and

Fig. 2 is a central section through thevalve, thermostat and pilot. i

I have shown the invention associated with I threaded into a boss 8 preferably formed'in-- tegral with the casing of the valve 5, a jam nut 9 being provided, if desired, to hold the tube 7 securely in the boss. A drill hole 10 extends from the interior of the valve cas- 111g 5 from the inlet chamberll thereof to the interior of the tube 7. z

The valveli is similar to the ordinary globe valve having a wall 12 separating the inlet chamber 11 from the outlet chamber 13, an enlarged aperture 14 being formed in the wall 12 and having at one side a beveled valve seat 1 5.adapted to receive the beveled edge of the valve 16 which is forced upwardly on its seat by some suitable resilient means, such as the helical spring 17. The valve 5 may be provided with an enlarged plug 18'threaded into the valve casing at 19 to the interior thereof.

The valve casing is provided with a boss 20 opposite the boss 8 and in which is located the bore 10, a central bore 21 being provided in both' bosses in which is journalled for lonpermit access to gitudinal motion an elongate rod 22 having its lower end 23 received in a central recess in the valve 16. The upper end of the rod 22 is reduced and threaded as shown at 24 and extends through thermostatic disk 25, being fixed thereto by a nut 26 or in any other suitable manner. The disk 25 is provided with one or more perforations 27 to permit the passage of gas from they interior of the tube 7 to the pilot nozzle 6.

The pilot nozzle 6 is provided with an enlargement 28.which may be integral therewith and which is provided withv an over hanging flange 29 adapted to engage the out or periphery of a substantially similar onlargement 30 which maybe integral with the tube 7, the thermostatic disk 25 being mounted between the members 28 and 30. In order that the disk-25 will not be so tightly grasped by the members 28 and 30 as to prevent its e cient operation, a spacer ring 31, which should be slightly (e. g. .005 inches) thicker than the disk is preferably provided between said members, the inner diameter of the ring form any part of the present invention.

The disk is preferably bi-metallic, being. formed of-two component disks welded together, the materials such as iron and brass I of the respective disks having different co- F.) and will snap 'back at a lower temperature ,eflicients of expansion. The disk 25 is normally cupped (as by swaging) in such direction that the component part having the higher coetficient'of expansion is on the concave side. -Consequentlyupon raising the temperature of the disk the unequal expansion of the materials forming the disk will cause a tendency to flatten the cupped surface until at a predetermined temperature a sudden curving inthe opposite direction occurs, which reversal of shape will be maintained until the temperature has been substantially lowered. Thereaftemyupon reaching a substantially lower temperature, the disk will snddenlyreturn to its initial shape. The materials and thickness of the component parts and the degree of curvature are so chosen that the disk will snap "in one direction whenheated to the desired temperature (e. g. 120

(e.'g. 100 F.). Suitable materials are sheet brass-andnickel steel having a thickness of .005 and. .005 inches respectively and suitable cupping fora inches in diameter is .02 inches.

- ti'cular combination of materials having difcause the reversal of curvature.

- the thermostatic disk heated during the op-'' It will be understood, however, that: the present invention is not limited to any parferent thermal coefiicients of expansion but is intended to embrace in its scope any combination of materials havin dissimilar thermal coeificients of expansion suflicient to Furthermore, the two materials comprising thecomposite thermostatic. disk may be secured toget-her in any desired manner by rivetin soldering, brazing or otherwise although it is preferred to unite the materials comprising the disk by wel or similar means to secure a substantial] mdivisible sheet.

' I provide an auxiliary means in addition to the pilot and'the main burner for keeping eration of-the pilot, such means in thepres ent instance-being one or more perforations 32 here shown as located in the pilot tube 6 above the thermostat and through which gas may flow'to-feed small flame jets closely adj acent to the member 28 which in turn imparts the heat to the thermostat both by conduction and radiation. It is contemplated that these jets may, if desired, be located-below the thermostatic disk rather than above it.

From the above description; the operatlon of the device should be obvious; During the I operation of either the burner, the pilot, or

the small jets, the thermostatic disk will be heated, and flexed in a position opposite to that shown in Fig. 2 so that the rod 22 will be in its lowermost position, thus keeping the valve 16 oil of its seat against the tension of the spring 17. If, however, the flames are extinguished for any reason, the thermostatic disk will cool below its critical point and snap abruptly into the position shown in Fig. 2, thus drawing the rod 22 upwardly. and permitting the spring 17 to close the valve 16 and thus cut ofl the gas feed to the main burner; While the gas fed to the/pilot is uninterrupted, the leakage from this source will be so slight as not to cause any appreciable danger. Inasmuch as many modifications of my invent-ion will appear to those skilled inthe art, I do not wish to be limited except by a bimetallic snap acting thermostat mounted at the free end of said rod, said lo'ng rod being enclosed by a pipe leading from said valve, flanges enclosing said thermostat,.a pilot nozzle mounted on one of said flanges adjacent said main burner to relight it when necessa of gas om said valve to go through said long p pe, through said thermostat and to said pilot burner.

2. The combination of a thermostatically and means for allowing a supply controlled pilot. burner and valve, said valve comprising 'two chambers connected by an opening, a valve member adapted to close or 'open said opening when necessary',zresilient means tending to keep said valve member in a closed position, a rod engaging said valve member and'having a thermostat mounted at its free end,a pipe connected to said valve and. w

surrounding said rod, flanges surrounding said thermostat, apilot nozzle mounted on one of said flanges, a main burner adapted 1 to screw on one side of said valve and directly communicating with one of said chambers,

a gas supply pipe adapted. toscrewon the other side of said valve and directly-com- 3. The combination with a gas and 'municating with the other chamber, said valve adapted to be connected so either one a gas supply pipe therefor of a'valve in the .pipe at a point remote from the burner so as not to receive an appreciable amount of heat therefrom, resilient means tending to keep said valve closed, a long rod engaging said valve,a snap acting thermostat mounted at the free end of said rod and having apertures therein, a pipe connected to said valve and surrounding said rod, flanges surrounding said thermostat, a pilot nozale supported by one of said flanges in proximity to said,

niainburner to relight it whereby said pilot nozzle obtains its supply of as from the main valve through the long pipe and thermostat.

Signed by me at Cambridge, Mass, this 14th day of September, 1927.

' RUFUS H. MAURER. 

